An arrangement for alternately feeding ammunition from two ammunition belts to an automatic fire arm is already known as per German published unexamined patent application No. 2,825,091 (continuation in part of German Pat. No. 2,303,953 which corresponds to U.S. Pat. No. 3,875,845). Such known arrangement provides for an alternate rapid switching over from one to the other feed mechanism, whereby after the switching over there is immediately ready for firing a cartridge from the corresponding feeder. The energy converter in this known arrangement consists of a gas piston having a gear rack, which piston is arranged transversely to the longitudinal axis of the weapon, and which gear rack meshingly engages in a right pinion wheel which in turn meshes with a left pinion wheel of the ammunition feed arrangement. In order to receive a respective return positioning spring, the pinion wheels are formed as cylindrical bushings having gear wheels mounted thereon, and these bushings are disposed with their rotational axes at both sides of the vertical plane which coincides with the bore axis of the gun barrel. The pinion wheels each mesh with a respective star wheel shaft which confronts the open mouth of each pinion wheel. The star wheel shafts are actuated by means of lateral slidable displacement towards the left (right) so that the end of the right (left) star wheel shaft of the corresponding feeder is meshingly form-lockingly engaged for actuating the respective feeder. The inlet openings lie in the immediate vicinity of a vertical bisecting plane at each side thereof, which is disposed between the star wheel shafts and which shafts are driven in opposite directions.
This known arrangement is complex, it requires a separate switching drive, which increases the number of individual parts of the total arrangement. Its disassembly, for example, when replacing parts is quite difficult and cumbersome.